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FreeBSD-SA-13:07.bind                                       Security Advisory
                                                          The FreeBSD Project

Topic:          BIND remote denial of service

Category:       contrib
Module:         bind
Announced:      2013-07-26
Credits:        Maxim Shudrak and the HP Zero Day Initiative, ISC
Affects:        FreeBSD 8.4-RELEASE and FreeBSD 9.x
Corrected:      2013-07-26 22:53:17 UTC (stable/8, 8.4-STABLE)
                2013-07-26 22:40:17 UTC (releng/8.4, 8.4-RELEASE-p2)
                2013-07-26 22:43:09 UTC (stable/9, 9.2-BETA2)
                2013-07-26 22:40:23 UTC (releng/9.1, 9.1-RELEASE-p5)
CVE Name:       CVE-2013-4854

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.

I.   Background

BIND 9 is an implementation of the Domain Name System (DNS) protocols.
The named(8) daemon is an Internet Domain Name Server.  The libdns
library is a library of DNS protocol support functions.

II.  Problem Description

Due to a software defect a specially crafted query which includes
malformed rdata, could cause named(8) to crash with an assertion
failure and rejecting the malformed query.  This issue affects both
recursive and authoritative-only nameservers.

III. Impact

An attacker who can send a specially crafted query could cause named(8)
to crash, resulting in a denial of service.

IV.  Workaround

No workaround is available, but systems not running the named(8) service
and not using the base system DNS utilities are not affected.

V.   Solution

Perform one of the following:

1) Upgrade your vulnerable system to a supported FreeBSD stable or
release / security branch (releng) dated after the correction date.

2) To update your vulnerable system via a source code patch:

The following patches have been verified to apply to the applicable
FreeBSD release branches.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

# fetch http://security.FreeBSD.org/patches/SA-13:07/bind.patch
# fetch http://security.FreeBSD.org/patches/SA-13:07/bind.patch.asc
# gpg --verify bind.patch.asc

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch

Recompile the operating system using buildworld and installworld as
described in <URL:http://www.FreeBSD.org/handbook/makeworld.html>.

Restart the named daemon, or reboot the system.

3) To update your vulnerable system via a binary patch:

Systems running a RELEASE version of FreeBSD on the i386 or amd64
platforms can be updated via the freebsd-update(8) utility:

# freebsd-update fetch
# freebsd-update install

VI.  Correction details

The following list contains the correction revision numbers for each
affected branch.

Branch/path                                                      Revision
- -------------------------------------------------------------------------
stable/8/                                                         r253696
releng/8.4/                                                       r253692
stable/9/                                                         r253695
releng/9.1/                                                       r253693
- -------------------------------------------------------------------------

To see which files were modified by a particular revision, run the
following command, replacing XXXXXX with the revision number, on a
machine with Subversion installed:

# svn diff -cXXXXXX --summarize svn://svn.freebsd.org/base

Or visit the following URL, replacing XXXXXX with the revision number:

<URL:http://svnweb.freebsd.org/base?view=revision&revision=XXXXXX>

VII. References

https://kb.isc.org/article/AA-01015

<URL:http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-4854>

The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-13:07.bind.asc
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